PHILADELPHIA (CBS) — Environmental activists opposed to proposed modifications to Pennsylvania’s smog regulations dominated the testimony during a hearing in Norristown on Wednesday.

Some were Philadelphia residents, others veterans, and others simply identified themselves as people who care about clean air. Each expressed respectful opposition to a proposal by the Department of Environmental Protection to modify regulations covering certain pollutants.

Robin Mann, lives in Rosemont, Delaware County. She charged the regulations would do little to stem the rising tide of asthma cases in the county caused by air pollutants.

“I am concerned that they are not effectively confronting the largest single source of smog-causing, NOX pollution, mainly coal-fired power plants,” Mann said.

Tom Shuster of Johnstown testified on behalf of the Sierra Club. He says the acronym adopted by the state for the regulations is RACT for Reasonably Available Control Technology.

“Instead, I would call it WACT – or worst available control technology,” Shuster said.

Sue Edward, a retired teacher and environmental activist from Swarthmore, says she’s disturbed the proposed changes would, in her reading of them, allow coal-fired power plants to not employ the latest technology to significantly reduce pollution.

“The proposed standard would allow these plants to continue to not use this technology and to belch pollutants at a rate as much as nine times greater than they have until now. I find this incomprehensible,” Edward said.

Russell Zerbo is from Philadelphia and represented the Clean Air Council. He testified a proposal allowing companies to using a rolling 30-day average for pollution measurements is unacceptable.

“DEP should require emissions reductions at all sources in a given system or facility and measured in a manner that is consistent with the protections of human health,” Zerbo said.

A DEP official said after the hearing there is a lot of misinformation about the proposed changes. She said the regulations actually require reductions in pollutants – not a relaxation of rules that would allow more of them to be expelled.

Pennsylvania’s proposal, expected to be adopted over the summer, still faces scrutiny from the federal Environmental Protection Agency.